<template>
  <div class="app-container">
    <h2 style="text-align: center;">发布新课程</h2>

    <el-steps :active="1" process-status="wait" align-center style="margin-bottom: 40px;">
      <el-step title="填写课程基本信息" />
      <el-step title="创建课程大纲" />
      <el-step title="提交审核" />
    </el-steps>

    <el-form label-width="120px">
      <el-form-item label="课程标题">
        <el-input v-model="courseInfo.title" placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写" />
      </el-form-item>

      <!-- 所属分类 TODO -->
      <el-form-item label="课程分类">
        <el-select
          v-model="courseInfo.subjectParentId"
          placeholder="一级分类"
          @change="subjectLevelOneChange"
        >
          <el-option
            v-for="subject in subjectList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"
          />
        </el-select>
        <el-select v-model="courseInfo.subjectId" placeholder="二级分类">
          <el-option
            v-for="subject in subjectTwoList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"
          />
        </el-select>
      </el-form-item>

      <!-- 课程讲师 -->
      <el-form-item label="课程讲师">
        <el-select v-model="courseInfo.teacherId" placeholder="请选择">
          <el-option
            v-for="teacher in teacherList"
            :key="teacher.id"
            :label="teacher.name"
            :value="teacher.id"
          />
        </el-select>
      </el-form-item>

      <el-form-item label="总课时">
        <el-input-number
          :min="0"
          v-model="courseInfo.lessonNum"
          controls-position="right"
          placeholder="请填写课程的总课时数"
        />
      </el-form-item>

      <!-- 课程简介 TODO -->
      <el-form-item label="课程简介">
        <tinymce :height="300" v-model="courseInfo.description" />
      </el-form-item>

      <!-- 课程封面 TODO -->
      <el-form-item label="课程封面">
        <el-upload
          :show-file-list="false"
          :on-success="handleAvatarSuccess"
          :before-upload="beforeAvatarUpload"
          :action="BASE_API+'/eduoss/fileoss'"
          class="avatar-uploader"
        >
          <img :src="courseInfo.cover" />
        </el-upload>
      </el-form-item>

      <el-form-item label="课程价格">
        <el-input-number
          :min="0"
          v-model="courseInfo.price"
          controls-position="right"
          placeholder="免费课程请设置为0元"
        />元
      </el-form-item>
      <div>
        <el-button :disabled="saveBtnDisabled" type="primary" @click="saveOrUpdate">保存并下一步</el-button>
      </div>
    </el-form>
  </div>
</template>

<script>
import courseApi from "@/api/edu/course";
import subjectApi from "@/api/edu/subject";
import teacherApi from "@/api/edu/teacher";
// 引入富文本组件
import Tinymce from "@/components/Tinymce";
export default {
  // 声明富文本组件
  components: { Tinymce },
  data() {
    return {
      // 保存按钮是否禁用
      saveBtnDisabled: false,
      courseInfo: {
        title: "",
        description: "",
        lessonNum: "",
        price: "",
        subjectId: "", //二级分类ID
        subjectParentId: "", //一级分类ID
        teacherId: "",
        cover: "https://edu478.oss-cn-hangzhou.aliyuncs.com/05254.jpg"
      },
      BASE_API: process.env.OSS_API,
      teacherList: [],
      subjectList: [],
      subjectTwoList: [],
      courseId: ""
    };
  },

  created() {
    this.init();
  },
  watch: {
    $route(to, from) {
      this.init();
    }
  },
  methods: {
    init() {
      if (this.$route.params && this.$route.params.id) {
        // 获取路由路径参数中courseId
        this.courseId = this.$route.params.id;
        // 查询课程信息
        this.getInfo();
      } else {
        this.courseInfo = {};
        this.courseInfo.cover =
          "https://edu478.oss-cn-hangzhou.aliyuncs.com/05254.jpg";
        this.courseId = "";
        this.teacherList = [];
        this.subjectList = [];
        this.subjectTwoList = [];
        this.getTeacherList();
        this.getOnSubject();
      }
    },
    getInfo() {
      courseApi.getCourseInfo(this.courseId).then(response => {
        this.courseInfo = response.data.courseInfo;
        /*
        解决下拉列表二级联动二级分类下拉列表数据回显为id而不是title的错误
        原因：数据回显的时候一级分类可以自动选中，但是二级分类由于数据源是空，只有courseInfo中有id数据，所以只会显示id值
          因此需要在数据回显的时候再次获取分类列表然后取出相应的二级分类列表，才能加载出title内容
        */
        // 1.查询出所有的分类，包含一级和二级分类
        subjectApi.getSubjectList().then(response => {
          // 2.获取所有一级分类
          this.subjectList = response.data.list;

          // 3.把所有的一级分类数组进行遍历，比较当前courseInfo里面一级分类id和所有一级分类id
          for (let i = 0; i < this.subjectList.length; i++) {
            //获取每个一级分类
            let oneSubject = this.subjectList[i];
            // 把courseInfo中的subjectParentId和每个一级分类id进行比较
            if (oneSubject.id === this.courseInfo.subjectParentId) {
              // 把一级分类的children属性赋值给二级分类下拉列表的数据源
              this.subjectTwoList = oneSubject.children;
            }
          }
        });
        this.getTeacherList();
      });
    },
    //上传成功
    handleAvatarSuccess(res, file) {
      this.$message({
        type: "success",
        message: res.message
      });
      this.courseInfo.cover = res.data.url;
    },
    //上传之前逻辑
    beforeAvatarUpload(file) {
      const isJPG = file.type === "image/jpeg";
      const isLt2M = file.size / 1024 / 1024 < 2;

      if (!isJPG) {
        this.$message.error("上传头像图片只能是 JPG 格式!");
      }
      if (!isLt2M) {
        this.$message.error("上传头像图片大小不能超过 2MB!");
      }
      return isJPG && isLt2M;
    },
    //一级分类绑定的change事件
    subjectLevelOneChange(value) {
      //alert(value);
      for (let i = 0; i < this.subjectList.length; i++) {
        if (this.subjectList[i].id === value) {
          this.subjectTwoList = this.subjectList[i].children;
          this.courseInfo.subjectId = "";
        }
      }
    },
    //查询所有的一级分类
    getOnSubject() {
      subjectApi.getSubjectList().then(response => {
        this.subjectList = response.data.list;
      });
    },
    //查询所有讲师
    getTeacherList() {
      teacherApi.getAllTeacher().then(response => {
        this.teacherList = response.data.items;
      });
    },
    // 添加课程信息
    saveOrUpdate() {
      if (this.$route.params && this.$route.params.id) {
        this.updateCourseInfo();
      } else {
        this.saveCourseInfo();
      }
    },
    updateCourseInfo() {
      this.saveBtnDisabled = true;
      courseApi.updateCourseInfo(this.courseInfo).then(response => {
        this.$message({
          type: "success",
          message: "修改课程基本信息成功"
        });
        
        //跳转到下一步
        this.$router.push({ path: "/course/chapter/" + this.courseId });
      }).catch(()=>{
        this.saveBtnDisabled = false
      })
    },
    saveCourseInfo() {
       this.saveBtnDisabled = true;
      courseApi.addCourseInfo(this.courseInfo).then(response => {
        //提示成功
        this.$message({
          type: "success",
          message: "添加课程基本信息成功"
        });
        this.courseId = response.data.courseId;
        this.saveBtnDisabled = false;
        //跳转到下一步
        this.$router.push({ path: "/course/chapter/" + this.courseId });
      })
      .catch(()=>{
        this.saveBtnDisabled = false
      })
    }
  }
};
</script>
  <style scoped>
.tinymce-container {
  line-height: 29px;
}
</style>
